I've experienced the opposite, even when typing in code that I've written myself. I tend to become robotic and refer to the paper I'm copying from, even when I should know what comes next. I might have gotten that habit from "those annoying typos" that I remember setting me back for hours when I used to copy programs for my old Commodore 64. I eventually became careful enough to average only one or two typos per program. Then one day I decided to split the copying between me and two friends who had no experience with that level of accuracy, and there were so many typos that I have to type everything over again!